AXTHiiMKDI s.K inn c \L\V1I.I.IA. 



159 



B. frutic'jsa Allman is a form of B. ramosa Van Bencden, which grows in agitated water. 

 The ohservations of GraefFe, 1884 (Arbeit. Zool. Inst. Wien., Bel. 5, p. 34()), are interesting in 

 the same connection, for he found that five distinct forms ot Bougainvillia medusx arise from 

 a hydroid apparently identical with Bougainvillia muscus Allman. It is therefore prohahle 

 that many of our so-called "species" of Bounim'illia are merely environmental races. The 

 hydroids of most of them remain unknown, or are not associated with any known medusa, 

 and many of the species are imperfectly described. The following descriptions must he con- 

 sidered as only tentative attempts to unravel the confusion which prevails at present and 

 which can not be dissipated until the hydroids of all or most of the species are discm 1 1< d. 

 Haeckel's 1879, genus " LizHsii" appears to apply only to immature specimens of lion- 

 gainvillia in which the oral tentacles have not \ et become branched. 



Tabuliir Synopsis nj the Medusa ) Bougainvillia.* Continued. 



*For B. obscitru Biini-vir and B. ghnella Torrry, see tclt. 



